package com.bjc.principle.singleton.type3;

/**
 * @program: DesignPattern
 * @description:
 * @author: bjc
 * @create: 2020-12-13 20:33
 */
public class SingletonTest03 {
    public static void main(String[] args) {
        Singleton instance1 = Singleton.getInstance();
        Singleton instance2 = Singleton.getInstance();
        System.out.println(instance1==instance2);
        System.out.println(instance1.hashCode());
        System.out.println(instance2.hashCode());
    }
}

//懒汉式  线程不安全
class Singleton{
    private static Singleton instance;

    private Singleton(){}

    //提供一个静态的共有方法，当使用到该方法时，才会创建instance
    //即懒汉式
    public static Singleton getInstance(){
        if (instance==null){
            instance = new Singleton();
        }
        return instance;
    }
}
